Question

Hy，

我有以下代码：

    public AppThread(SocketChannel socketChannel){
    this.socketChannel=socketChannel;
  }

      public void run(){
            try{
              ByteBuffer bb = ByteBuffer.allocate(11);    
              socketChannel.read(bb);
              //byte[] b = new byte[bb.capacity()];
             // bb.get(b, 0, 11);
              System.out.println(bb.toString());
              byte[] a = new byte[11];
              CharBuffer cb = bb.asCharBuffer();
              System.out.println(cb);
              bb.get(a);

              App app=new App();
             // String an = new String(b);
              //String zodie = Zodie.getZodie(an);
              //b = new byte[zodie.length()];
              //b = zodie.getBytes();
              bb.clear();
              //bb.put(b);
              socketChannel.write(bb);
              socketChannel.close(); 
            }
            catch(IOException e){
               System.err.println("Server comunication error : "+e.getMessage());
            }  
          }
}

和接收字符串并返回字符串的zodie静态方法。

如何将写入SocketChannel的字符串作为参数传递给zodiac静态方法。

我提到在客户端我发送一个字节数组，我已经检查过了，没关系。

客户方：

  byte[] a = an.getBytes();
        System.out.println(new String(a));
    ByteBuffer bb=ByteBuffer.allocate(11);
    // Varianta 1
    bb.put(a);
    // Varianta 2
    // LongBuffer lb=bb.asLongBuffer();
    // lb.put(0,m).put(1,n);
    try{
      sc.write(bb);
      bb.clear();
      sc.read(bb);
      // Varianta 1
      //a = new byte[bb.remaining()];
      zodie=bb.toString();
      // Varianta 2
      // r=lb.get(0);
      System.out.println("Zodia : "+ zodie);
      sc.close();

此致

我收到服务器错误：

Server ready... 
    java.nio.HeapByteBuffer[pos=1 lim=11 cap=11]

    Exception in thread "pool-1-thread-1" java.nio.BufferUnderflowException
        at java.nio.HeapByteBuffer.get(Unknown Source)
        at java.nio.ByteBuffer.get(Unknown Source)
        at server.AppThread.run(AppThread.java:27)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

Answer 1

问题出在客户端。我使用了一个charbuffer作为一个包装器

Scanner scanner=new Scanner(System.in);
String m;
System.out.println("Enter the date (yyyy-mm-dd) :");
m=scanner.next()+" ";

CharBuffer  c = CharBuffer.wrap(m);
System.out.println("Sending date ...: " + c);
ByteBuffer b = Charset.forName("ISO-8859-1").encode(c);
 b.compact();
System.out.println("Bytebuffer has the capacity of "+ 
b.capacity() + "pointer position on bytebuffer is on: "+ b.position() + " and the limit is:" + b.limit());
b.flip();

在服务器端：

CharBuffer  c;
    ByteBuffer bb = ByteBuffer.allocate(11);    
     System.out.println("Server allocated a number of 11 octets to ByteBuffer");

    socketChannel.read(bb);
    bb.flip();//sets the Position to 0 and limit to the number of bytes to be read.
    CharBuffer c = Charset.forName("ISO-8859-1").decode(bb);
           System.out.println("Got " + c);

    byte[] byteArray = new byte[11];
    bb.get(byteArray);
    System.out.println("Server got from client the string: " +new String(byteArray));
    String an = new String(byteArray);
     bb.clear();

Answer 2

你的问题是在行bb.get（a）;

您指定11个字符数组作为参数，因此方法get（）要求bb包含11个字符，但它只包含1个。

原因是当你向套接字写入11个字符时，它们不能保证一次到达。他们可以分成小组，如1和10或5和6等。

您需要查看并读取套接字并检查read（）调用的结果。一些事情：

for (;;) {
   int numberOfBytesRead =socket.read(buf);
   if (numberOfBytesRead < 0) { break; }
}

从套接字通道读取字符串

2 个答案: